Compositions for planarization of metal-containing surfaces using halogens and halide salts

ABSTRACT

A planarization method includes providing a metal-containing surface (preferably, a Group VIII metal-containing surface, and more preferably a platinum-containing surface) and positioning it for contact with a polishing surface in the presence of a planarization composition that includes a halogen and a halide salt.

This is a continuation of application Ser. No. 10/771,050, filed on Feb.3, 2004 and issued as U.S. Pat. No. 6,861,353, which is a continuationof application Ser. No. 10/032,049, filed on Dec. 21, 2001 and issued asU.S. Pat. No. 6,730,592, which are hereby incorporated by reference intheir entirety for all purposes.

FIELD OF THE INVENTION

The present invention relates to methods for planarization ofmetal-containing (preferably, Group VIII, and more preferably,platinum-containing) surfaces, particularly in the fabrication ofsemiconductor devices.

BACKGROUND OF THE INVENTION

Films of metals and metal oxides, particularly the heavier elements ofGroup VIII, are becoming important for a variety of electronic andelectrochemical applications. This is at least because many of the GroupVIII metal films are generally unreactive, resistant to oxidation orretard the diffusion of oxygen, and are good conductors. Oxides ofcertain of these metals also possess these properties, although perhapsto a different extent.

Thus, films of Group VIII metals, their alloys, and metal oxides,particularly the second and third row metals (e.g., Ru, Os, Rh, Ir, Pd,and Pt) have suitable properties for a variety of uses in integratedcircuits. For example, they can be used in integrated circuits forbarrier materials, for example. They are particularly suitable for useas barrier layers between the dielectric material and the siliconsubstrate in memory devices. Furthermore, they are suitable as the plate(i.e., electrode) itself in capacitors.

Platinum is one of the candidates for use as an electrode for highdielectric capacitors. Capacitors are the basic charge storage devicesin random access memory devices, such as dynamic random access memory(DRAM) devices, static random access memory (SRAM) devices, and nowferroelectric memory (FE RAM) devices. They consist of two conductors,such as parallel metal or polysilicon plates, which act as theelectrodes (i.e., the storage node electrode and the cell platecapacitor electrode), insulated from each other by a dielectric material(a ferroelectric dielectric material for FE RAMs). Thus, there is acontinuing need for methods and materials for the processing of GroupVIII metal-containing films, preferably, platinum-containing films.

Many surfaces that result during the formation of Group VIIImetal-containing films, particularly in the wafer fabrication ofsemiconductor devices, do not have uniform height, and therefore, thewafer thickness is also non-uniform. Further, surfaces may have defectssuch as crystal lattice damage, scratches, roughness, or embeddedparticles of dirt or dust. For various fabrication processes to beperformed, such as lithography and etching, height non-uniformities anddefects at the surface of the wafer must be reduced or eliminated. Also,excess material may need to be removed to form a structure withselectivity relative to the underlying substrate. Planar removal of asubstrate's top surface is also used to isolate certain featureselectrically. Various planarization techniques are available to providesuch reduction and/or elimination. One such planarization techniqueincludes mechanical and/or chemical-mechanical polishing (abbreviatedherein as “CMP”).

The process of planarization is used to remove material, and preferablyachieve a planar surface, over the entire chip and wafer, sometimesreferred to as “global planarity.” Conventionally, the process ofplanarization, and particularly CMP, involves the use of a wafer holderthat holds a wafer, a polishing pad, and an abrasive slurry thatincludes a dispersion of a plurality of abrasive particles in a liquid.The abrasive slurry is applied so that it contacts the interface of thewafer and the polishing pad. A table or platen has a polishing padthereon. The polishing pad is applied to the wafer at a certain pressureto perform the planarization. At least one of the wafer and a polishingpad are set in motion relative to the other. In some planarizationprocesses, the wafer holder may or may not rotate, the table or platenmay or may not rotate and/or the platen may be moved in a linear motionas opposed to rotating. There are numerous types of planarization unitsavailable which perform the process in different manners. Alternatively,the polishing pad and abrasive slurry may be replaced by a fixedabrasive article that includes a plurality of abrasive particlesdispersed within a binder adhered to at least one surface of a backingmaterial.

The planarization of a surface that includes platinum and other GroupVIII metals typically involves mechanical polishing, as opposed tochemical-mechanical polishing, because they are relatively chemicallyinert and/or have relatively few volatile products. Such mechanicalpolishing uses alumina, silica, or other abrasive particles to removethe metal physically. Unfortunately, mechanical polishing tends to smear(e.g., deform) the metals, leaving metal over undesired portions of thewafer surface, and leaving scratches in either the metal itself or otherareas on the wafer surface. Also, many commercially available abrasiveslurries do not effectively planarize platinum or other Group VIIImetal-containing surfaces either because no material is removed or theresultant surface has defects therein.

Thus, there is still a need for methods for planarizing an exposedsurface of a substrate that includes platinum and/or other Group VIIImetals, particularly in the fabrication of semiconductor devices.

SUMMARY OF THE INVENTION

The present invention provides methods that overcome many of theproblems associated with the planarization of a surface, particularlyone that includes platinum, another of the Group VIIIB metals, and/or aGroup IB metal. Preferably, the methods of the present invention areeffective for the planarization of a surface containing at least one ofthe second and third row metals of Group VIIIB (i.e., Groups 8, 9, and10, which includes Rh, Ru, Ir, Pd, Os, and Pt) and Group IB (i.e., Auand Ag). More preferably, the methods of the present invention areeffective for the planarization of a surface containing at least one ofRh, Ru, Ir, Pd, and Pt. Such a surface is referred to herein as a“metal-containing surface.” That is, a “metal-containing surface” refersto an exposed region having a metal present, preferably at least onemetal of Group VIIIB and Group IB present. In such an exposed region,the metal is preferably present in an amount of at least about 10 atomicpercent, more preferably at least about 20 atomic percent, and mostpreferably at least about 50 atomic percent, of the composition of theregion, which may be provided as a layer, film, coating, etc., to beplanarized (e.g., via chemical-mechanical or mechanical planarization orpolishing) in accordance with the present invention. The surfacepreferably includes one or more Group VIIIB and/or Group IB metals inelemental form or an alloy thereof (with each other and/or one or moreother metals of the Periodic Table), as well as oxides, nitrides, andsilicides thereof. More preferably, the surface includes (and mostpreferably, consists essentially of) one or more Group VIIIB and/orGroup IB metals in elemental form or an alloy of such metals only.

The methods of the present invention involve planarizing a surface usinga planarization composition that preferably includes ahalogen-containing compound and a halide salt therein (dissolved ordispersed therein). A preferred group of halogen-containing compoundsinclude the halogens (e.g., F₂, Cl₂, Br₂, and I₂), the interhalogens(e.g., ClBr, IBr, ICl, BrF, ClF, ClF₃, BrF₃, ClF₅, IF₅, and IF₇), andhalogen-generating compounds (e.g., XeF₂, HgF₂, SF₄, alkyl halides, andcomplexes of X₂ with organic bases). The halide salts can be inorganicsalts (e.g., NaI, KCl, KBr, and NH₄F) or organic salts (e.g., Et₄NBr,Me₃NHCl, and Me₄NF).

Herein, as is conventionally understood, “planarizing” or“planarization” refers to the removal of material from a surface,whether it be a large or small amount of material, either mechanically,chemically, or both. This also includes removing material by polishing.As used herein, “chemical-mechanical polishing” and “CMP” refer to adual mechanism having both a chemical component and a mechanicalcomponent, wherein corrosion chemistry and fracture mechanics both playa roll in the removal of material, as in wafer polishing.

Preferably, the halogen-containing compound is present in thecomposition in an amount of at least about 0.1% by weight, and morepreferably, in an amount of no greater than about 50% by weight. Mostpreferably, the halogen-containing compound is present in thecomposition in an amount of about 1% to about 10% by weight.

Preferably, the halide salt is present in the composition in an amountof at least about 0.1% by weight, and more preferably, in an amount ofno greater than about 50% by weight. Most preferably, the halide salt ispresent in the composition in an amount of about 1% to about 10% byweight.

The planarization composition can optionally include abrasive particles,thereby resulting in an abrasive slurry, and be used in planarizationtechniques with conventional polishing pas that do not have abrasiveparticles embedded therein. Alternatively, the planarization compositionwithout abrasive particles therein can be used with fixed abrasivearticles (also referred to as abrasive polishing pads) in place ofconventional polishing pads. Such fixed abrasive articles include aplurality of abrasive particles dispersed within a binder adhered to atleast one surface of a backing material. If the halogen-containingcompound and/or halide salt are not stable in a composition withabrasive particles (i.e., an abrasive slurry), they may be provided byseparate delivery systems and/or in separate compositions and mixed atthe point of use. Alternatively, the composition may be stabilized bythe addition of surfactants, chelating agents, phase transfer catalysts,emulsifiers, or other solvents.

In one aspect of the present invention, a planarization method isprovided that includes: positioning a metal-containing surface of asubstrate (preferably, a semiconductor substrate or substrate assemblysuch as a silicon wafer) to interface with a polishing surface;supplying a planarization composition in proximity to the interface; andplanarizing the metal-containing surface. The metal-containing surfaceincludes a metal selected from the group consisting of a Group VIIIBmetal, a Group IB metal, and a combination thereof. The planarizationcomposition includes a halogen-containing compound and a halide salt.Herein, “a” or “an” or “the” mean “one or more” or “at least one.” Thus,various combinations of halogen-containing compounds and halide saltscan be used in the planarization compositions described herein.

In another aspect of the invention, there is provided a planarizationmethod that includes: providing a semiconductor substrate or substrateassembly including at least one region of a platinum-containing surface;providing a polishing surface; providing a planarization composition atan interface between the at least one region of platinum-containingsurface and the polishing surface; and planarizing the at least oneregion of platinum-containing surface; wherein the planarizationcomposition includes a halogen-containing compound and a halide salt.

In yet another aspect of the invention, there is provided aplanarization method that includes: positioning a metal-containingsurface of a substrate to interface with a polishing surface, whereinthe metal-containing surface includes a metal selected from the groupconsisting of a Group VIIIB metal, a Group IB metal, and a combinationthereof; supplying a planarization composition in proximity to theinterface; and planarizing the substrate surface. In this embodiment,the planarization composition includes: a halogen-containing compoundselected from the group consisting of F₂, Cl₂, Br₂, I₂, ClBr, IBr, ICl,BrF, ClF, ClF₃, BrF₃, ClF₅, IF₅, IF₇, XeF₂, HgF₂, SF₄, alkyl halides,and complexes of X₂ with organic bases, and combinations thereof; and ahalide salt selected from the group consisting of NaI, KCl, KBr, NH₄F,Et₄NBr, Me₃NHCl, Me₄NF, and combinations thereof.

In still another aspect of the invention, there is provided aplanarization method that includes: providing a semiconductor substrateor substrate assembly including at least one region of aplatinum-containing surface; providing a polishing surface; providing aplanarization composition at an interface between the at least oneregion of platinum-containing surface and the polishing surface; andplanarizing the at least one region of platinum-containing surface. Inthis embodiment, the planarization composition includes: ahalogen-containing compound selected from the group consisting of F₂,Cl₂, Br₂, I₂, ClBr, IBr, ICl, BrF, ClF, ClF₃, BrF₃, ClF₅, IF₅, IF₇,XeF₂, HgF₂, SF₄, alkyl halides, and complexes of X₂ with organic bases,and combinations thereof; and a halide salt selected from the groupconsisting of NaI, KCl, KBr, NH₄F, Et₄NBr, Me₃NHCl, Me₄NF, andcombinations thereof.

The present invention also provides a planarization method for use informing an interconnect that includes: providing a semiconductorsubstrate or substrate assembly having a patterned dielectric layerformed thereon and a metal-containing layer formed over the patterneddielectric layer, wherein the metal-containing layer includes a metalselected from the group consisting of a Group VIIIB metal, a Group IBmetal, and a combination thereof; positioning a first portion of apolishing surface for contact with the metal-containing layer; providinga planarization composition in proximity to the contact between thepolishing surface and the metal-containing layer, and planarizing themetal-containing layer, wherein the planarization composition includes ahalogen-containing compound and a halide salt.

The present invention further provides a planarization method for use informing an interconnect that includes: providing a semiconductorsubstrate or substrate assembly having a patterned dielectric layerformed thereon and a metal-containing layer formed over the patterneddielectric layer, wherein the metal-containing layer includes a metalselected from the group consisting of a Group VIIIB metal, a Group IBmetal, and a combination thereof; positioning a first portion of apolishing surface for contact with the metal-containing layer; providinga planarization composition in proximity to the contact between thepolishing surface and the metal-containing layer; and planarizing themetal-containing layer. In this embodiment, the planarizationcomposition includes: a halogen-containing compound selected from thegroup consisting of F₂, Cl₂, Br₂, I₂, ClBr, IBr, ICl, BrF, ClF, ClF₃,BrF₃, ClF₅, IF₅, IF₇, XeF₂, HgF₂, SF₄, alkyl halides, and complexes ofX₂ with organic bases, and combinations thereof; and a halide saltselected from the group consisting of NaI, KCl, KBr, NH₄F, Et₄NBr,Me₃NHCl, Me₄NF, and combinations thereof.

As used herein, “semiconductor substrate or substrate assembly” refersto a semiconductor substrate such as a base semiconductor layer or asemiconductor substrate having one or more layers, structures, orregions formed thereon. A base semiconductor layer is typically thelowest layer of silicon material on a wafer or a silicon layer depositedon another material, such as silicon on sapphire. When reference is madeto a substrate assembly, various process steps may have been previouslyused to form or define regions, junctions, various structures orfeatures, and openings such as capacitor plates or barriers forcapacitors.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A and 1B are cross-sectional illustrations of one portion of awafer before and after a planarization process has been performed inaccordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides methods of planarization of a surfacethat includes platinum and/or one or more of the other Group VIIIBand/or Group IB metals. The Group VIIIB metals are also referred to asthe Group VIII elements or transition metals of Groups 8, 9, and 10 ofthe Periodic Table. The Group IB metals include the copper triad (Cu,Ag, and Au). The second and third row metals of Groups IB and VIIIB arepreferred and include Rh, Ru, Ir, Pd, Pt, Os, Au, and Ag. Particularlypreferred surfaces that can be planarized according to methods of thepresent invention include Rh, Ru, Ir, Pd, and/or Pt. Such a surface isreferred to herein as a metal-containing surface (this refers to thosecontaining second and/or third row transition metals).

Herein, a “metal-containing surface” includes an exposed region having ametal present. In such an exposed region, the metal is preferablypresent in an amount of at least about 10 atomic percent, morepreferably at least about 20 atomic percent, and most preferably atleast about 50 atomic percent, of the composition of the region, whichmay be provided as a layer, film, coating, etc., to be planarized (e.g.,via chemical-mechanical or mechanical planarization or polishing) inaccordance with the present invention.

The planarization of such surfaces, particularly a surface that includesplatinum, typically involves mechanical methods with relatively hardparticles such as alumina (Al₂O₃) and/or silica (SiO₂) particles, whichcan cause smearing and the formation of defects rather than the cleanremoval of the material. Surprisingly, the use of a planarizationcomposition that includes a halogen-containing compound and a halideeither in combination with a plurality of abrasive particles in thecomposition or with a fixed abrasive article reduces, and ofteneliminates, the problem of defect formation.

The planarization composition can be used in slurry planarization (i.e.,in a conventional planarization process in which the planarizationcomposition includes the abrasive particles with a polishing pad thatdoes not include abrasive particles) or in fixed abrasive planarization.Thus, as used herein, a “polishing surface” refers to a polishing pad ora fixed abrasive article. Preferably, slurry planarization is used inthe methods of the present invention. Preferably, when present in theplanarization composition, the composition includes the abrasiveparticles in an amount of about 1% by weight to about 30% by weight, andmore preferably, about 1% by weight to about 15% by weight, based on thetotal weight of the composition.

A wide variety of abrasive particles can be used either in an abrasiveslurry or in a fixed abrasive article. Typically, such abrasiveparticles range in particle size (i.e., the largest dimension of theparticle) on average from about 10 nanometers (nm) to about 5000 nm, andmore often about 30 nm to about 1000 nm. For preferred embodiments,suitable abrasive particles have an average particle size of about 100nm to about 300 nm.

Examples of suitable abrasive particles include, but are not limited to,alumina (Al₂O₃), silica (SiO₂), ceria (CeO₂), titania (TiO₂), zirconia(ZrO₂), manganese dioxide (MnO₂), tantalum dioxide (TaO₂), and niobiumoxide (NbO₂). Preferred abrasive particles include alumina (Al₂O₃),silica (SiO₂), ceria (CeO₂), titania (TiO₂), and zirconia (ZrO₂).Various combinations of abrasive particles can be used if desired.

In certain methods in accordance with the present invention, preferably,a majority of the plurality of abrasive particles (either in an abrasiveslurry or in a fixed abrasive article) are Al₂O₃ particles.

The planarization composition includes a halogen-containing compound anda halide salt therein (dissolved or dispersed therein). Preferred suchcompounds form X₃ ⁻ species in situ. Although not intending to belimiting, it is believed that this species is the chemically reactivespecies that assists in removal of the metal.

A preferred group of halogen-containing compounds include the halogens,the interhalogens, and halogen-generating compounds. The halogensinclude F₂, Cl₂, Br₂, and I₂. The interhalogens generally exist in fourstoichiometries: XY, XY₃, XY₅, and XY₇, where X is the heavier halogen.A few ternary compounds are also known, such as IFCl₂ and IF₂Cl. For thehexatomic series, only the fluorides are known. Preferred interhalogencompounds for use in the present invention include, for example, ClBr,IBr, ICl, BrF, ClF, ClF₃, BrF₃, ClF₅, IF₅, and IF₇. Thehalogen-generating compounds include XeF₂, HgF₂, SF₄, alkyl halides, andcomplexes of X₂ with organic bases, such as NR₃ (wherein R is an organicgroup, preferably a C₁-C₃₀ organic group), dioxane, crown ethers,azacrowns, etc.

A more preferred group of halogen-containing compounds includes XeF₂,Br₂, Cl₂, and I₂. A most preferred group of halogen-containing compoundsincludes XeF₂ and Br₂. The halogen-containing compounds may be solid,liquid, or gas at room temperature. Preferably, they are soluble in aliquid medium used in the planarization composition. Variouscombinations of such halogen-containing compounds can be used.

Preferably, the halogen-containing compound is present in thecomposition in an amount of at least about 0.1% by weight, and morepreferably, in an amount of no greater than about 50% by weight, basedon the total weight of the composition. Most preferably, thehalogen-containing compound is present in the composition in an amountof about 1% to about 10% by weight, based on the total weight of thecomposition.

The halide salts can be inorganic salts (e.g., NaI, KCl, KBr, and NH₄F)or organic salts (e.g., Et₄NBr, Me₃NHCl, and Me₄NF). A preferred groupof halide salts includes KBr, KCl, and NH₄F. The halide salts aretypically solids at room temperature. Various combinations of suchhalogen-containing compounds can be used.

Preferably, the halide salt is present in the composition in an amountof at least about 0.1% by weight, and more preferably, in an amount ofno greater than about 50% by weight, based on the total weight of thecomposition. Most preferably, the halide salt is present in thecomposition in an amount of about 1% to about 10% by weight, based onthe total weight of the composition.

The halogen-containing compound(s) and halide salt(s) are typicallydissolved in, although they may be dispersed in, a liquid medium in theplanarization composition. The liquid medium is typically water,although organic liquids such as methanol, acetonitrile, acetone,glycols may be used, particularly if used in a mixture with water.Various combinations of liquids can be used if desired.

Other additives can be included as well for desired effects. Forexample, to enhance stability of a composition of the present inventionsurfactants, chelating agents, phase transfer catalysts, emulsifiers, orother solvents can be used. Surfactants (e.g., polyethylene glycol,polyoxy ethylene ether, or polypropylene glycol) can also be used toenhance wettability and reduce friction. Other additives include, butare not limited to, thickeners (e.g., CARBOPOL) to achieve a desiredviscosity and buffering agents (e.g., organic acid salts) to achieve adesired pH. Preferably, the composition is an aqueous solution of thesecomponents.

For certain embodiments, the planarization composition includes aplurality of abrasive particles. For other embodiments, theplanarization composition is essentially free of abrasive particles whensupplied to the interface of a fixed abrasive article and the workpiecesurface. However, in these latter embodiments, it is contemplated thatplanarization is accomplished by one or both of the fixed abrasivearticle and/or abrasive particles that may be removed from the fixedabrasive article at the fixed abrasive/surface interface in combinationwith the planarization composition. In any event, abrasive particles aretypically not present in the composition as initially applied, i.e.,they are not supplied from a source external to the polishing interface.

Preferably, a method in accordance with the present invention isconducted at atmospheric pressure and at a temperature of about 40° F.(about 4° C.) to about 145° F. (about 62° C.), and more preferably at atemperature of about 24° C. to about 115° F. (46° C.). In manyinstances, however, it would be desirable to maintain a temperature ator below ambient temperature during planarization of metal with a fixedabrasive article. This is seldom practical in slurry planarization(i.e., in a conventional planarization process in which theplanarization composition includes the abrasive particles) where a lowerslurry temperature likely results in poor dispersion of abrasiveparticles in the slurry composition during planarization. Accordingly,elevated temperatures are typically utilized during slurryplanarization, although too high a temperature could result in too low aconcentration of oxidizing gas in the planarization composition.

Various planarization assemblies or units for performing methods of theinvention are readily available and are clearly contemplated by thescope of the present invention as described in the accompanying claims.Such planarization assemblies can create an interface between apolishing pad or a fixed abrasive article and the substrate surface(e.g., wafer surface) in various manners, e.g., rotation, movement,pressure, etc., to achieve planarization. A planarization composition istypically introduced at or near the interface, by a variety of methodssuch as by dripping, spraying, or other dispensing means, or bypresoaking a polishing pad, although other locations and methods ofintroduction can be used.

In a typical planarizing machine, a polishing pad is fixed on a platenor table, a carrier assembly that includes a substrate holder to supportthe substrate (e.g., wafer) typically using suction, and a driveassembly to rotate and/or reciprocate the platen and/or a drive assemblyto rotate and/or translate the substrate holder during planarization.Thus, conventional planarizing machines rotate the carrier assembly, thepolishing pad, or both the carrier assembly and the polishing pad. Ingeneral, the planarizing machines are used to produce a planarizationreaction product at the surface of a substrate whose hardness is lessthan the hardness of the abrasive particles and whose adhesion to thesubstrate is less than the original surface material; and to remove thereaction product using the abrasive particles.

Typically, the polishing pads, with or without abrasive particlesembedded therein, are disk-shaped and rotatable about a fixed plane andaxis at constant or variable speeds. Typically, the speed of rotationranges from about 2 revolutions per minute (rpm) to about 200 rpm.

Typically, a polishing pad is presoaked and continually rewet with theplanarization composition. If the polishing pad does not includeabrasive particles embedded therein, the planarization compositionincludes abrasive particles, which is then referred to as an abrasiveslurry. The planarization composition may be applied to the interfacebetween a polishing pad and a substrate surface using a variety oftechniques. For example, the component parts of the composition may beapplied separately and mixed at the interface or immediately beforecontacting the interface. The planarization composition can be appliedby pumping it through the pad. Alternatively, it can be applied at theleading edge of the pad, although this may not provide uniformdistribution of the planarization composition across the surface beingplanarized, which is desirable.

The polishing pad can be any of a wide variety of conventional polishingpads that are used with abrasive slurries. They can be made from amaterial such as polyurethane, polyester, acrylic, acrylic estercopolymers, polytetrafluoroethylene, polypropylene, polyethylene,cellulose, cellulose esters, polamides, polyimides, polysiloxane,polycarbonates, epoxides, phenolic resins, etc. They include, forexample, a polyurethane-based foam material, wherein the foam cell wallsof the pad aid in removal of reaction products at the wafer surface andthe pores within the pad assist in supplying slurry to the pad/waferinterface. They can include convex or concave features, which can beformed by embossing a surface pattern. For example, a polishing pad canhave continuous grooves in concentric ellipses in the surface of the padfor more uniform slurry delivery and more effective debris removal.Commercially available polishing pads can be obtained under the tradedesignations “URII,” “Sycamore,” and “Polytex” from Rodel, Phenix, Ariz.Examples of polishing pads are also disclosed in U.S. Pat. No. 6,039,633(Chopra).

In general, a fixed abrasive article includes a plurality of abrasiveparticles dispersed within a binder that forms a three-dimensional fixedabrasive element that is adhered to one surface of a backing material.They are described, for example, in U.S. Pat. No. 5,692,950 (Rutherford,et al.) and International Patent Publication WO 98/06541. Commerciallyavailable fixed abrasive articles can be obtained from Tokyo SumitsuKageki and Ebera Corporation, both of Japan, and Minnesota Mining andManufacturing Company (3M Company) of St. Paul, Minn. An example of apreferred fixed abrasive article is a ceria-based pad commerciallyavailable from 3M Company under the trade designation “SWR 159.” Suchfixed abrasive articles can be used with a planarization composition asdescribed herein with or without abrasive particles in the planarizationcomposition.

It is highly desirable to have a high polishing rate (i.e., the rate atwhich material is removed from the substrate) to reduce the duration ofeach planarizing cycle, the polishing rate is preferably uniform acrossthe substrate to produce a uniformly planar surface. Preferably, thepolishing rate is controlled to provide accurate, reproducible results.Also, preferably, the planarization process is carried out in one cycle(i.e., one step). That is, for the removal of any material from aparticular surface, there is only one planarization cycle without anyintervening rinse cycles. This planarization process is then typicallyfollowed by a post-planarization clean process in which abrasiveparticles are not used.

The figures provide further information about the methods of theinvention. FIG. 1A illustrates one portion of a wafer 10 prior toplanarization in accordance with the present invention. The waferportion 10 includes a substrate assembly 12 having a patterneddielectric layer 16 formed thereon. Such a patterned dielectric layer 16can be used in a variety of structures, particularly a capacitorstructure. The patterned dielectric layer 16 can be formed of anymaterial that provides electrical isolation between metal regions (e.g.,silicon dioxide, silicon nitride, or BPSG). An electrode layer 19 isthen formed over the substrate assembly 12 and the patterned dielectriclayer 16. The electrode layer 19 may be platinum or any other suitableconductive second or third row Group VIIIB or Group IB metal-containingmaterial. Generally, as shown in FIG. 1A, the nonplanar upper surface 13of electrode layer 19 is subjected to planarization or other processingin accordance with the present invention. The resulting wafer 10, asshown in FIG. 1B, includes an upper surface 17 planarized such that thethickness of the wafer 10 is substantially uniform across the entirewafer 10 so that the wafer now includes electrically conducting regions14 isolated within the patterned dielectric material 16 forming acapacitor structure.

FIG. 1 is shown only to illustrate a surface having nonuniformities,such as height differences, in the fabrication of semiconductor devices.The present invention is not limited to use with nonplanar surfaces. Thepresent invention is also beneficial for use with substantially planarsurfaces. For example, the methods in accordance with the presentinvention is beneficial during the whole planarization process, even atthe end of the process when the surface being planarized is in asubstantially planar state.

The following example is offered to further illustrate the variousspecific and preferred embodiments and techniques. It should beunderstood, however, that many variations and modifications may be madewhile remaining within the scope of the present invention.

EXAMPLE

A test sample was cut from a wafer containing a blanket layer of 2700 Åof sputtered platinum metal. Several locations on the sample weremeasured for sheet resistance before any polishing, directly correlatingthe metal thickness to the sheet resistance. A slurry was prepared byaddition of 0.2 mL of Br₂ (Mallinckrodt Specialty Chemicals, Paris, Ky.)and 0.43 g of KBr (Aldrich Chemical Co., Milwaukee, Wis.) to 30 mL ofRodel CMP slurry containing Al₂O₃ as the abrasive. The sample was fixedto the carrier on a Beuhler Minimet 1000 polisher and was polished on aRodel polishing pad upon which several milliliters of the preparedslurry was added. Polishing was carried out using a pressure of 15pounds and a speed of 50 revolutions per minute (rpm). After 2 minutesthe sample was rinsed and dried, and the sheet resistance measuredagain. The higher sheet resistance values yielded a calculated estimateof 900 Å of film removed (or a removal rate of approximately 450 Å perminute). By comparison, the same slurry without the added halogen andhalide salt yielded little change in the sheet resistance of a similarsample, and caused only scratches and some areas of film delaminatedfrom the substrate.

The foregoing detailed description and example have been given forclarity of understanding only. No unnecessary limitations are to beunderstood therefrom. The invention is not limited to the exact detailsshown and described, for variations obvious to one skilled in the artwill be included within the invention defined by the claims. Forexample, while the description above focused on planarization ofsemiconductor-based substrates, the compositions and methods of theinvention are also applicable to, for example, polishing glasses andcontact lenses, as one of many other possible applications. The completedisclosures of all patents, patent documents, and publications listedherein are incorporated by reference, as if each were individuallyincorporated by reference.

1. A planarization composition comprising: a halogen-containing compoundselected from the group consisting of a halogen; an interhalogen; ahalogen-generating compound selected from the group consisting of XeF₂,HgF₂, SF₄, alkyl halides, and complexes of halogen with organic bases;and combinations thereof; and a halide salt, wherein the halogencontaining compound and the halide salt are separately delivered.
 2. Theplanarization composition of claim 1 wherein the halogen-containingcompound is selected from the group consisting of F₂, Cl₂, Br₂,I₂, ClBr,IBr, ICl, BrF, ClF, ClF₃, BrF₃, ClF₅, IF₅, IF₇, XeF₂, HgF₂, SF₄, alkylhalides, and complexes of halogen with organic bases, and combinationsthereof.
 3. The planarization composition of claim 1 wherein the halidesalt is an inorganic salt.
 4. The planarization composition of claim 3wherein the inorganic halide salt is selected from the group consistingof NaI, KCl, KBr, NH₄F, and combinations thereof.
 5. The planarizationcomposition of claim 1 wherein the halide salt is an organic salt. 6.The planarization composition of claim 5 wherein the organic salt isselected from the group consisting of Et₄NBr, Me₃NHCl, Me₄NF, andcombinations thereof.
 7. The planarization composition of claim 1wherein the halogen-containing compound is present in the planarizationcomposition in an amount of at least about 0.1% by weight and the halidesalt is present in the planarization composition in an amount of atleast about 0.1% by weight.
 8. The planarization composition of claim 1further comprising an additive.
 9. The planarization composition ofclaim 8 wherein the additive is selected from the group consisting of asurfactant, a chelating agent, a phase transfer catalyst, a thickener, abuffer, an emulsifier, and combinations thereof.
 10. The planarizationcomposition of claim 1 further comprising a plurality of abrasiveparticles.
 11. A planarization composition comprising: ahalogen-containing compound selected from the group consisting of F₂,Cl₂, Br₂, I₂, ClBr, IBr, ICl, BrF, ClF, ClF₃, BrF₃, ClF₅, IF₅, IF₇,XeF₂, HgF₂, SF₄, alkyl halides, and complexes of halogen with organicbases, and combinations thereof; and a halide salt selected from thegroup consisting of NaI, KCl, KBr, NH₄F, Et₄NBr, Me₃NHCl, Me₄NF, andcombinations thereof, wherein the halogen containing compound and thehalide salt are separately delivered.
 12. The planarization compositionof claim 11 wherein the halogen-containing compound is present in theplanarization composition in an amount of about 1% to about 10% byweight.
 13. The planarization composition of claim 11 wherein the halidesalt is present in the planarization composition in an amount of about1% to about 10% by weight.
 14. The planarization composition of claim 11further comprising an additive.
 15. The planarization composition ofclaim 14 wherein the additive is selected from the group consisting of asurfactant, a chelating agent, a phase transfer catalyst, a thickener, abuffer, an emulsifier, and combinations thereof.